1. Field of the Invention
The present invention relates to a lubrication system of an axle assembly used in a power transmission system, such as one for a motor vehicle.
2. Description of the Prior Art
A conventional axle assembly of a motor vehicle comprises a differential gear and a pair of drive shaft assemblies penetrating both sides thereof. A solid annular spacer is provided between a side bearing assembly and a differential carrier. The drive shafts are ordinarily disposed within the axle shaft tubes.
Normally in operation, lubricant from the differential carrier penetrates the axle shaft tubes due to the splashing of the lubricant by rotation of a differential ring gear, or by other means.
When axle assemblies are of full floating type, the wheel ends do not require lubrication. Therefore, the lubricant entrapped inside the axle tubes should be returned to the differential carrier. For this purpose, the differential carrier of conventional design is formed with a cast-in drain-back channel facing downward.
Alternatively, when axle assemblies are of semi-floating type, the wheel ends require adequate lubrication. In this case, it is desirable to keep certain amount of lubricant inside the axle shaft tubes. For this purpose, the differential carrier is formed with the cast-in drain-back channel facing upward that allows lubricant to be trapped in the axle tube bores.
Many differential carriers are structurally substantially identical except for the radial position of the drain-back channel. The type of the axle assembly the differential carrier is used in determines the radial position of the drain-back channel. This requires at least two different variations of the differential carriers: for full-floating type axle assemblies and for semi-floating type axle assemblies each provided with the cast-in drain-back channels, however positioned differently.
Moreover, with the current method of production, the differential carrier may have all the requirements needed for a particular axle assembly except the cast-in drain-back channel is in the wrong position. Thus, a new carrier has to be made.
Accordingly, it is the intent of this invention to overcome these shortcomings of the prior art, and more specifically, to eliminate the cast-in drain-back channels in the differential carriers.